Convoy electrons in coincidence with Hq+and Heq+outgoing projectiles traversing carbon foils

We have measured convoy electrons produced by the passage of light ions (H + at 150, 200, 250 keV/u and He + at 100, 150, 200 keV/u) through equilibrium thickness carbon foils (ϱ x = 5 μg/cm 2 ) in coincidence with the charge states q f = 0, 1 resp. q f = 0, 1, 2 of the outgoing projectiles. All charge state fractions were registered simultaneously by a position sensitive parallel-plate-avalanche detector (PPAD). The yield of coincident convoy electrons Y c ( q f ) is normalized to the same number of outgoing projectiles and mirrors the fraction of the emergent ions of each charge state q f . The FWHM of the coincident convoy electron peak is found to be independent of q f . A transport length λ c for convoy electrons in the range of the mean free path of free electrons is deduced from the data. This result is in contradiction with recent measurements for D + (150 keV/u).